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bhalldorson

Cummins ISB 6.7 Overheating

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Original owner of 2008 Fleetwood Expedition with 48K miles. Just started occasional overheating alarm for no apparent reason such as load, hills or outside temperature. New water pump and thermostat, fan clutch new at 20K miles, radiator steam cleaned by Freightliner two days ago when water pump replaced, belt good.

After I pull off road and allow engine to idle for a few minutes, temperature drops to normal and stays in normal range for several hundred miles.

Any ideas? Currently east of El Paso heading for Tucson, then through the mountains and home to Nebraska.

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You mention that Freightliner cleaned the radiator. MUCH more critically, did they clean the FRONT (front of coach) of the CAC (Charge Air Cooler)? This can not be done from the back of the coach-- it has to be done from the bedroom/closet-- access to the front of the CAC.

The front of the CAC is where the vast majority of the cooling package is deposited. It really needs to be cleaned (from the front) at least once a year.

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Do a search there are threads on here on the procedure to use in cleaning a rear radiator coach and cleaning the CAC and radiator is very important on all coaches but a must on rear radiator. I would also check to make sure my crank case vent is venting behind the CAC and radiator.

Walt

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Seem like there are very many people experiencing overheating in the 2008 & 2009 Freightliner/Fleetwood models. I see a lot of complaints about the Hayden fan clutch that Freightliner installed on the Cummins engine. You have to wonder...

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Thanks for the info. Have appointment with Cummins Monday morning. They agree this is a probability. I got through the closet floor, but that is just the top of the fan shroud. Now looking for info on how to access through the floor.

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I don't know if yours is the same as my Bounder. Try lifting the bed-- you may have to pull the aft part of the bed frame. There is a section with carpet on it that will pull out toward the passenger side and lift up. Under that is a panel with some screws in it like the closet floor.

Good luck

Bill

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I have a 2008 Cummins ISB. We left California a week ago and came across on I-40 through Kingman and on to Flagstaff. One time my temp went up to 212 but that was my fault as I did not do my normal control.

My normal control is to not leave it on cruise but to press down on the accelerator until the cruise and accelerator are equal then take it off of cruise. Then, NEVER move the foot on the accelerator. Let the engine do the work from that point on. It may be necessary to down shift manually to keep the engine RPM's up. Sometime the transmission wants to go into 4th but I'll downshift to 3-3 to keep the RPM's up. My slowest speed up any of the hills was between 30-35 mph and passing trucks going slower. When I hit that 212 temperature I down shifted and within 30 seconds or less the temp started dropping. On most of the long hills my temp was between 203 and 205˚.

That's my story and I'm sticking to it.

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Thanks Mr. Wolfe!! Cummins Rocky Mountain in Phoenix pulled the radiator and the charge air cooler. Major air blockage that is not obvious by simply feeling air flow when the engine is running. Looked like a large bird's nest of grass and mud. In the future, this area will receive a flushing after every trip. Certainly Freightliner dealers in Wichita and Salina have some explaining to do. Tried to add photo's but failed. Thanks again everyone for the input.

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